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Re: [DOM3 Events] Type of deltaX, deltaY and deltaZ of WheelEvent should be float

From: Olli Pettay <Olli.Pettay@helsinki.fi>
Date: Wed, 02 Feb 2011 11:44:31 +0200
Message-ID: <4D49277F.8060400@helsinki.fi>
To: Masayuki Nakano <masayuki@d-toybox.com>
CC: "www-dom@w3.org" <www-dom@w3.org>
On 02/02/2011 07:06 AM, Masayuki Nakano wrote:
> Hello.
> http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html#events-WheelEvent
> Current WheelEvent spec defines the type of deltaX, deltaY and detaZ as
> long. But I think they should be float.

I already brought this up during the last conference call and
we all agreed that this is what we should do. Thanks for
noticing the problem.


> On Windows, native mouse wheel event comes with delta value which means
> 120 is one unit. The system settings of Windows specify how many lines
> or one page should be scrolled by 120. On Vista and later, the delta
> value of each native event may be less than 120. Therefore, it may mean
> non-integer lines or pages. E.g., 60 with one page scroll means half of
> a page. 30 with 1 line scroll means 0.333333... line scroll.
> If we round up the delta value to integer, the scroll will be faster
> than other applications. On the other hand, if we round down the delta
> value, the scroll will be slower or stop (if delta < 1px).
Received on Wednesday, 2 February 2011 09:45:03 UTC

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